Boring bar



Jam. 27, 1948. 'ZEMPEL 2,435,065

BORING BAR Filed July 20, 1946 INVENTOR EDWARD A. ZEMPEL ATTORNEYS Patented Jan. 27, 1948 UNITED STATES PATENT OFFICE 5 Claims.

This invention appertains to boring bars and more particularly to a, novel cutter insert therefor.

One of the primary objects of this invention is to provide a boring bar having a novel cutter insert embodying a pair of floating cutter blocks carrying the cutter or blades with means for automatically centering the blocks relative to the insert and the bar.

Another salient object of the invention is to provide means for adjusting the floating blocks for size or wear from either side of the insert without removing the insert from the bar, the centering device automatically locking and holdingthe blocks in correct position relative to each other and the bar.

A further object of this invention is to provide a micrometer ad ustment for the floating blocks, whereby the blocks can be accurately and conveniently set to the exact desired size.

A further important object of my invention is to provide novel means for assoc ating the floating blocks with a center supporting block, whereby the floating cutter blocks will be adequately supported from the supporting block.

A still further object of the invention is to provide means for removably associating cutter blades or tips with the floating cutter blocks, whereby new tips can be associated with the blocks when the original tips are worn down beyond a predetermined point. I

A still further object of my invention is to provide novel means for associating the insert with the boring bar itself, whereby the boring bar will not be weakened and whereby the insert will be efiectively supported by the bar.

With these and other objects in view the invention consists in the novel construction, arrangement and formation of parts, as will be hereinafter more specifically described, claimed and illustrated in the accompanying drawings, in which drawings Figure 1 is a fragmentary longitudinal sectional view through a boring bar showing my novel insert connected therewith, the bar being ready for use.

Figure 2 is a diametric sectional view through the bar taken substantially on the line 22 of Figure 1 looking in the direction of the arrows.

Figure 3 is a fragmentary top plan view of the boring bar with my novel insert, parts of the view being shown broken away and in section.

Figure 4 is a fragmentary longitudinal center sectional view through the bar and insert, the section being taken substantially on the line I i of Figure 3, the view showing, however, the floating blocks after adjustment from one side and prior to the centering thereof.

Figure 5 is a diametrical sectional view taken on the line 55 of Figure 4 looking in the direction of the arrows.

Figure 6 is a view similar to Figure 5 but showing the floating cutter blocks after the centering thereof.

Figure '7 is a diametrical sectional view through the boring bar and insert taken substantially on the line 'I'I of Figure l looking in the direction of the arrows.

Referring to the drawing in detail, wherein similar reference characters designate corresponding parts throughout the several views the letter B generally indicates the boring bar and I the insert therefor.

In accordance with this invention, the boring bar B adjacent to its front end is provided with a diametrically extending slot Ill. The insert I is of an exact size to fit snugly within the slot, as will be apparent from the drawings.

The insert I includes a center guide and sup porting block II and a pair of floating cutter blocks I2 and I3. These blocks i2 and I3 are of identical shape and their inner edges are provided with notches I3 in which is fitted the supporting guide block II. The forward ends of the blocks I2 and I 3 receive the cutting blades or tips I4 and I5 and these tips can be formed from high speed tool steel or tungsten carbide. The inner ends of the tips or cutters carry shanks I6 which are received in sockets Il formed in the floating blocks. The inner ends of these blocks I2 and I3 can be provided with knockout openings I8 communicating withthe sockets, so that a suitable tool can be inserted in the sockets for forcing out the tips. If desired set screws can be threaded into the floating blocks against the shanks to insure against the accidental displacement of the cutters or tips from the blocks.

Attention is called to the fact that a, part of the tip rests against the forward wall of the boring bar.

The floating blocks are adapted to be guided and adjusted on the center guide and supporting block II and consequently this guide and supporting block II adjacent to its forward end is provided with a guide opening I9 which extends centrally through the block. This o ening receives guide pins 20 and the pins 20 are held against movement by set screws 2| which are threaded into openings 22 in the floating blocks I2 and I3. The openings 22 align with the opening I9 in the center guide and supporting block and the pins also extend into the openings 22.

In rearof the opening I9, the center and sup: porting block II is provided with a similar open ing 23 and this opening has fitted therein a guide sleeve 24. The guide sleeve 24 is internally threaded and these threads are of a certain deflnite pitch for a purpose which will be later set forth. The terminals of the sleeve 24 are slidably fitted in openings 25 formed in the floating blocks and outer ends of theseopenings are countor-bored to provide stop shoulders26. Adjustthe outer surface of the floating blocks l2 and.

' l3 around the heads of the screws can be calibrated as at 29. The heads of the screws themselves can be provided with an indicating pointer 30 for cooperation with the markings,

From the description so far, it can be seen that the floating blocks are slidably mounted both on the pins 20 and on the guide sleeve 24. Thus twisting movement. of the, floatin blocks relative to the center and supporting block H. is prevented.

The floating. blocks. on one side and adjacent to their iorward endsv are provided with beveled or inclined surfaces 3L Threaded diametrically into the boring bar B is an adjusting. and centering, screw 32. The inner end of this screw is tapered as. at 33 and the taper on. the screw matches the. bevel surface. 3]. onthe floating blocks L2 and t3.

When it is desired to adiustthefloating, blocks l2 and 13. and the cutter or tips. 1,4. and. [5, say to-aclarger size one of the screws 21'or 28 is turned 4 ametrically extending slot therein adjacent to its forward end, a removable insert snugly fitted in said slot including a center? guide; block, a pair of like companion normally floating cutter blocks slidable on the center supporting block, cutter tips carried by the floating cutter blocks, guide pins between the center supporting block and the floating cutter blocks, a guide sleeve disposed in rear of said guide pins and extending through the center supporting block and the floating cutter blocks, said sleeve having its opposite terminals internally threaded, and headed screws threaded into the opposite ends of the sleeve, the heads of these screws being adapted .to. bear against the floating cutter blockssaid cutter tips being disposed forwardly of the guide means and the sleeve and adjusting screws.

3. A boring tool comprising a bar having a diametrically extending slot thereinadjacent to its forward end, a. removable insert snugly fitted in said slot. including. a center guide block, a pair of like companion normally floatingcutter blocks slidable on the center supporting block,,, cutter in. the desired directionto-feed. the same outwardis and the number. of turns. of the selected. screw or partial. turn is carefully computed and each turn of. a. screw moves the, same an exact distance, known tothe; operator. Prior to the ad.- j ustment of. the screws 91 or 28 the centering screw 32. is threaded outwardly a desired distance, see Fig. 5,. this allows. movement. of. the cutter blocks. After the. selected screw has been adjusted, thecentering screw is. then turned. tight into; the boring. bar and. its, tapered leading end 3.3..will. engage against the. beveled surfaces of. the cutter blocks, and automatically center.- the cutter blocksin the, boring bar..

It is to.- be also understood that. the-centering screw. 32 can beturned outas shown. in Figurefi to-nelease cutter blocks, so that. the same can float in. the bar iorreaming or finishing.

Thebar itselt is not weakened in. any. way and the slotjis. reinforced by.- the fact that the insert occupies. the slot and his to. be also. noted that the slotextendsthrough thedcad center of the Itis to be. also noted. thatthe'adiustmentand guide for the floating blocks is back of the cuttips carried by the floating cutter blocks, guide pins between the center supporting block and the floating. cutter blocks, a guide sleeve disposed. in rear of said guide pins and extending through the center supporting block and the floating cutter blocks, said sleeve having its opposite terminals internally threaded, and headed screws threaded into the opposite ends of the sleeve, the heads" of these screws being adapted to", bear against the floating cutter blocks, said floating cutter blocks being calibratedaround the heads of the screws and said head's being provided with indicating points for cooperation withsaid calibrations.

' 4. A boring, tool comprising a bar havinga diametrically extending slot therein adjacent to its forward end, a removable insert snugly fitted in ting edge of the: tips. i4. and- I5 andthis. feature or insures. the. proper taking up of the. cutting strains.

Changes in. details may. be made: without. departing from.the spirit or scope of my invention but what I, claimas new. is:

1; As boring, tool. comprising. a. barhaving a diametrically extending slot. therein. adjacent to its, forward; end, a removable insert. snugly fitted inlsaid.slot;including a center. guide; block, a pair oilikacompanionznormally floating; cutter blocks slidable .on..the center supportingblock, cutter tips carried;- by the. floating cutter. blocks, guide pins betweenrthe: center supporting block andthefloat; ing cutter; blocka a: guide. sleeve. disposed: in: rear 0f:sai.d.guide pins andiextending through .thecem ter; supporting block. ands-the. floating cutter blocks; said sieeve having its. opposite. terminals internally; threaded, and headedscrewsr threaded into,the. opposite. ends of. the sleeve,.the. heads of these. screwsbeing adapted to. bear ainst'the fronting cutterblocksb 2. A boring tooicomprising a bar'having' a di said slot including a center guide block, pair of likecompanion normally floating cutter blocks slidable on thecentersupporting block, cutter tips carried by the floating cutter blocks, guide pins between the center supporting block and the floating cutter blocks, a guide sleeve disposed in rear of said guide pins and extending" through the center supporting block and the floating cut ter blocks; said sleeve having its opposite terminals internally threaded, and headed screws threaded into the opposite ends of the sleeve, the heads of these screws being adapted to bear against the floating cutter blocks, and means carried by the bar for centering'and locking the floating cutter blocks in said bar.

51 An insert for boring bars comprising'a center supporting block, a pair of normally floating companion cutter blocks slidably mounted on the EDWARD A. ZEMPEL.

REFERENCES CITED:

The following references are of recordin. the

flle of this patent:

UNITED STATES PATENTS Number Name Date; 1,062,225 Crowley May'2il; 1 91B 

